import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:go_router/go_router.dart';
import 'package:shuffle/features/auth/domain/auth_status.dart';
import 'package:shuffle/features/auth/domain/auth_user.dart';
import 'package:shuffle/features/auth/presentation/auth_routes.dart';
import 'package:shuffle/features/auth/presentation/providers/auth_providers.dart';
import 'package:shuffle/features/home/presentation/home_screen.dart';
import 'package:shuffle/l10n/app_localizations_de.dart';
import 'package:shuffle/l10n/app_localizations_en.dart';

import '../../../helpers/pump_app.dart';
import '../../auth/presentation/auth_ui_support.dart';

final _de = AppLocalizationsDe();
final _en = AppLocalizationsEn();

const _user = AuthUser(id: 'u1', email: 'a@example.test', emailConfirmed: true);

void main() {
  late MockAuthRepository repository;

  setUp(() => repository = MockAuthRepository());

  /// Pumps the home route plus the real auth routes. [status] `null` means
  /// the status stream has no value yet (loading); [statusStream] overrides it.
  Future<void> open(
    WidgetTester tester, {
    AuthStatus? status = const AuthStatus.signedOut(),
    Stream<AuthStatus>? statusStream,
    Locale locale = const Locale('de'),
    ThemeMode themeMode = ThemeMode.light,
    double? textScale,
    Size size = const Size(400, 800),
  }) async {
    tester.view.physicalSize = size;
    tester.view.devicePixelRatio = 1;
    addTearDown(tester.view.reset);
    final router = GoRouter(
      routes: [
        GoRoute(path: '/', builder: (_, _) => const HomeScreen()),
        ...authRoutes,
      ],
    );
    addTearDown(router.dispose);
    final stream =
        statusStream ??
        (status == null
            ? const Stream<AuthStatus>.empty()
            : Stream.value(status));
    await pumpApp(
      tester,
      router: router,
      locale: locale,
      themeMode: themeMode,
      textScale: textScale,
      settle: status != null || statusStream != null,
      overrides: authUiOverrides(
        repository,
        locale: locale,
        extra: [authStatusProvider.overrideWith((ref) => stream)],
      ),
    );
    if (status == null && statusStream == null) await tester.pump();
  }

  final promptCard = find.byKey(const Key('sign_in_prompt'));
  final signInButton = find.byKey(const Key('sign_in_prompt_sign_in'));
  final registerButton = find.byKey(const Key('sign_in_prompt_register'));

  group('#49 Krit. 1: Anmelde-Hinweis auf der Startseite', () {
    testWidgets('abgemeldet: Hinweis mit zwei Knöpfen und Platzhaltertext', (
      tester,
    ) async {
      await open(tester);
      expect(promptCard, findsOneWidget);
      expect(find.text(_de.signInPromptTitle), findsOneWidget);
      expect(find.text(_de.signInPromptBody), findsOneWidget);
      expect(find.text(_de.signInPromptSignIn), findsOneWidget);
      expect(find.text(_de.signInPromptRegister), findsOneWidget);
      expect(find.text(_de.homePlaceholderMessage), findsOneWidget);
    });

    testWidgets('QUE-05 Krit. 2: abgemeldet, en: englische Texte', (
      tester,
    ) async {
      await open(tester, locale: const Locale('en'));
      expect(find.text(_en.signInPromptTitle), findsOneWidget);
      expect(find.text(_en.signInPromptBody), findsOneWidget);
      expect(find.text(_en.signInPromptSignIn), findsOneWidget);
      expect(find.text(_en.signInPromptRegister), findsOneWidget);
    });

    testWidgets('angemeldet: kein Hinweis, Platzhaltertext bleibt', (
      tester,
    ) async {
      await open(tester, status: const AuthStatus.signedIn(_user));
      expect(promptCard, findsNothing);
      expect(find.text(_de.homePlaceholderMessage), findsOneWidget);
    });

    testWidgets('Laden (kein erster Wert): kein Hinweis', (tester) async {
      await open(tester, status: null);
      expect(promptCard, findsNothing);
      expect(find.text(_de.homePlaceholderMessage), findsOneWidget);
    });

    testWidgets('Fehler im Statusstrom: Hinweis wird angezeigt', (
      tester,
    ) async {
      await open(tester, statusStream: Stream.error(StateError('boom')));
      expect(promptCard, findsOneWidget);
    });

    testWidgets('KTO-01 Krit. 4: Tipp auf „Anmelden“ öffnet den LoginScreen', (
      tester,
    ) async {
      await open(tester);
      await tester.tap(signInButton);
      await tester.pumpAndSettle();
      expect(find.byKey(const Key('login_screen')), findsOneWidget);
    });

    testWidgets(
      'KTO-01 Krit. 1: Tipp auf „Konto erstellen“ öffnet den RegisterScreen',
      (tester) async {
        await open(tester);
        await tester.tap(registerButton);
        await tester.pumpAndSettle();
        expect(find.byKey(const Key('register_screen')), findsOneWidget);
      },
    );

    testWidgets('breit (1280 dp): Karte höchstens 480 dp breit, zentriert', (
      tester,
    ) async {
      await open(tester, size: wideScreenSize);
      final rect = tester.getRect(promptCard);
      expect(rect.width, lessThanOrEqualTo(480));
      expect(rect.center.dx, closeTo(wideScreenSize.width / 2, 1));
    });
  });

  group('QUE-06: Barrierefreiheit des Anmelde-Hinweises', () {
    for (final (name, size, theme) in [
      ('Handy hell', const Size(400, 800), ThemeMode.light),
      ('Handy dunkel', const Size(400, 800), ThemeMode.dark),
      ('breit hell', wideScreenSize, ThemeMode.light),
    ]) {
      testWidgets('QUE-06 Krit. 1-3: Guidelines ($name)', (tester) async {
        final handle = tester.ensureSemantics();
        await open(tester, size: size, themeMode: theme);
        await expectLater(tester, meetsGuideline(androidTapTargetGuideline));
        await expectLater(tester, meetsGuideline(iOSTapTargetGuideline));
        await expectLater(tester, meetsGuideline(labeledTapTargetGuideline));
        await expectLater(tester, meetsGuideline(textContrastGuideline));
        handle.dispose();
      });
    }

    testWidgets(
      'QUE-06 Krit. 1: Überschrift, Text und Knöpfe sind eigene Semantics-Knoten',
      (tester) async {
        final handle = tester.ensureSemantics();
        await open(tester, size: wideScreenSize);
        expectSeparateSemantics(
          tester,
          title: _de.signInPromptTitle,
          bodyKey: const Key('sign_in_prompt_body'),
          bodyLabel: _de.signInPromptBody,
          buttonKey: const Key('sign_in_prompt_sign_in'),
          buttonLabel: _de.signInPromptSignIn,
        );
        expectButtonSemantics(tester, registerButton, _de.signInPromptRegister);
        handle.dispose();
      },
    );

    for (final locale in const [Locale('de'), Locale('en')]) {
      testWidgets(
        'QUE-06 Krit. 3: Schriftgröße 200 % ohne Überlauf (${locale.languageCode})',
        (tester) async {
          await open(
            tester,
            textScale: 2,
            size: const Size(320, 640),
            locale: locale,
          );
          expect(tester.takeException(), isNull);
          // The page scrolls: dragging moves the content, the buttons stay
          // reachable and tappable.
          final before = tester.getTopLeft(registerButton).dy;
          await tester.drag(
            find.byType(SingleChildScrollView),
            const Offset(0, -200),
          );
          await tester.pump();
          expect(tester.getTopLeft(registerButton).dy, lessThan(before));
          await tester.ensureVisible(registerButton);
          await tester.pump();
          expect(
            tester.getSize(registerButton).height,
            greaterThanOrEqualTo(48),
          );
          await tester.tap(registerButton);
          await tester.pumpAndSettle();
          expect(find.byKey(const Key('register_screen')), findsOneWidget);
        },
      );
    }

    testWidgets(
      'QUE-06 Krit. 4: Tab-Reihenfolge Anmelden -> Konto erstellen, Enter löst aus',
      (tester) async {
        await open(tester);
        bool focusIn(Finder button) {
          final focus = FocusManager.instance.primaryFocus;
          if (focus?.context == null) return false;
          return find
                  .descendant(
                    of: button,
                    matching: find.byElementPredicate(
                      (e) => e == focus!.context,
                    ),
                  )
                  .evaluate()
                  .isNotEmpty ||
              find
                  .ancestor(
                    of: find.byElementPredicate((e) => e == focus!.context),
                    matching: button,
                  )
                  .evaluate()
                  .isNotEmpty;
        }

        await tester.sendKeyEvent(LogicalKeyboardKey.tab);
        await tester.pump();
        expect(focusIn(signInButton), isTrue);
        await tester.sendKeyEvent(LogicalKeyboardKey.tab);
        await tester.pump();
        expect(focusIn(registerButton), isTrue);
        // Visible focus: keyboard navigation switches to traditional highlight
        // mode and the button holds the primary focus (the focus ring comes
        // from the focused state of the theme).
        expect(
          FocusManager.instance.highlightMode,
          FocusHighlightMode.traditional,
        );
        expect(FocusManager.instance.primaryFocus?.hasPrimaryFocus, isTrue);

        await tester.sendKeyEvent(LogicalKeyboardKey.enter);
        await tester.pumpAndSettle();
        expect(find.byKey(const Key('register_screen')), findsOneWidget);
      },
    );

    testWidgets('QUE-06 Krit. 4: Leertaste löst „Konto erstellen“ aus', (
      tester,
    ) async {
      await open(tester);
      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
      await tester.pump();
      await tester.sendKeyEvent(LogicalKeyboardKey.space);
      await tester.pumpAndSettle();
      expect(find.byKey(const Key('register_screen')), findsOneWidget);
    });
  });
}